Here are some lessons Spencer Clark has learned in three years working for the federal government:

When he goes to boring meetings, he sits at the table so no one will think he's a slacker. He knows when to keep his mouth shut. He's not the best thing since sliced bread. Baby boomers have a lot to offer, even if they drive him crazy.

The earnest 27-year-old with a goatee who bikes with his laptop to his job administering the Paperwork Reduction Act for the Environmental Protection Agency is helping to rescript one of the oldest cliches in Washington. A new movement is shaking up the federal bureaucracy, as an expanding pool of idealistic, results-oriented Gen X and Yers challenges the predictability and authority-driven rules of the World War II generation and the pay-your-dues baby boomers who followed.

Many of the younger workers are arriving in a hiring spree. The Obama administration hopes to fill 50,000 to 60,000 entry-level jobs in the next year, the largest burst since the Kennedy era. The administration is creating positions in security, public health, defense -- and is pushing many jobs held by outside contractors inside the government.

The pipeline at the entry and mid-levels is opening fast as close to half a million baby boomers and older workers head out the door in the next four years.

After watching government responses to such crises as Hurricane Katrina and the Gulf of Mexico oil spill, this new crop of federal workers wants to do better. Almost one in three of the 142,690 federal workers hired last year was 29 or younger, while more than one in four were between 30 and 39, a demographic that's reshaping the bureaucracy -- and creating tension and opportunity along the way.

In 10 years, about 400,000 of the 2 million federal workers will be younger than 35, government personnel experts say.

With private-sector job prospects for college graduates at their bleakest in years, government leaders see a window to attract new talent, as well as compete with Teach for America and the Peace Corps for the service-minded.

Seeking risk

For all their bravado, today's young feds know they are following a Great Society generation that nurtured programs such as Medicare and Medicaid, sent the first man to the moon, and gave birth to the very agency Clark bikes to every morning. They know, too, that those baby boomers, a generation with their own sense of mission, will take expertise and institutional memory with them when they go.

Young workers are restless for risk. They don't want to be GS-9s forever. They expect to be consulted and engaged -- no head-down, it-has-always-worked-this-way chain of command here. They're digital natives, too, who want to manage acquisition contracts on Twitter and who think crowd sourcing and cloud computing are the future of customer service. "Sure, I deal with a lot of bureaucratic drudgery," said Clark, whose first job in government was shelving library books in high school. "But I came here because of the mission."

His job is to help reduce the burden of paperwork on the public. He was working for a labor union and fresh off two years as a missionary in France after college when the EPA called three years ago. Clark likes the agency's mission "to protect human health and the environment."

These are many of the young people who sent Barack Obama to the White House, where the president has repeated John F. Kennedy's call to service from 49 years ago and pledged to make working for the government cool again.